Multiphase technology has proven key for areas like automotive power and data centre, and the results of previous investments are starting to emerge.
Analogue and mixed-signal solutions provider Intersil has come a long way from the 1990s. Nick Flaherty talks to Mark Downing, senior vice president of corporate strategy and infrastructure and industrial power products, and Philip Chesley, senior vice president for precision products, about the direction of the company.
“Intersil’s history in power is long and deep,” said Downing. “In the mid ‘90s, we provided Intel’s VRM multiphase solutions for high current loads for processors and over the years the company has refined its IP and performance in that space serving everything from desktops and notebooks and now for servers.”
This multiphase technology has proven key for areas as diverse as automotive power and data centre systems and the results of previous investments are starting to emerge.
“Three years ago we looked at the businesses and saw the key was in power management, so the decision was to focus around that (apart from automotive and radiation hard, but even in those markets we have a strong focus) so we doubled down on power and we are just now starting to reap the benefits of that decision,” he said.
“We’d seen this continual trend in power towards higher power density and if you put it in context of the load, whether a processor, an ASIC, FPGA or embedded SoC, what you are seeing is many more voltage rails. This puts a premium on being able to power those chips in the smallest possible space. That’s one trend that we saw and based on that we increased our investment in power modules because we saw a need for power density and ease of use. These days customers don’t have time to design power systems and in many cases don’t have the expertise and they are under pressure to deliver a solution quickly.”
This creates a competitive tension with the open frame power supply makers as the semiconductor companies take on more of the module market using IC packaging techniques.
“Companies like Intersil and our competitors have taken on the task of taking the controller, driver, FET, inductor and some of the passives and integrating those into an IC package, so we call it a module but it’s in an IC package that has the same ease of use as an open frame module but in a smaller footprint. In some cases we supply controllers and integrated FET switching modules to vendors but they tend to focus on higher power,” said Downing.
__Figure 1:__ *It may look like a chip but the ISL8273M is a power module for data centre servers in IC packaging.*
“We are pushing higher currents up to 80A and we are looking at how to take that beyond 100A so we are infringing on their space going forward, but we tend to coexist in many customer applications–a 48V IBC [intermediate bus converter] for example will still be using an open frame module,” he said. “For a given current level we have a better thermal performance in the packaging but there are limits and we continue to look at ways to expand that. It also depends on innovation in the packaging so we work closely with subcontractors to drive that innovation.”
“Another trend we saw was digital power, and we acquired Zilker Labs in 2008 because we saw the trend back then,” said Downing. “We realised three years ago that we had not invested enough in digital power which was coming of age but we are seeing early indications of that emerging in the hyperscale data centres who are now adopting the technology,” he said.
The other strand to Intersil’s power strategy is automotive.
“In the automotive space one of the real changes is how to provide functional safety and performance at the same time so we decided to invest more in that area,” said Philip Chesley, Senior Vice President for Precision Products. “We had a good footprint through video decoders in automotive designs and we had a small but growing power position around that footprint so we expanded that. We are still doing that [those decoder designs] but we are really focussed in two areas—the first is cell balancing for full electric vehicle (EV) designs, basically anything that’s using a lithium ion battery.”
“The other area we are investing in is the emerging 48V system to meet emission standards—what’s driving the transition is the fines that are going to be imposed on car makers. The 48V system fits between a start-stop system and a full hybrid and that allows them to meet the emission goals. The issues with VW have made things go faster,” he said.
Here the technical challenge is to handle between 1 and 3kW bidirectionally, which requires the multiphase capability that is core IP at Intersil. “There’s enough momentum in Europe and Asia for the initial stage where you will use a 48V system to recapture more power than you can with today’s 12V alternators to give smoother operation, and that’s definitely going to happen. It takes longer than everyone thinks, but that will continue,” he said.
Battery management is going to grow fast and for Chesley, the charge time is equally important as range. If you can charge the batteries quickly then range is less of an issue, he says. “That’s all power management problems as well as battery chemistry,” he said. “We are somewhat agnostic as to the battery chemistry – it does drive the accuracy of the cell balancing and the voltages but for the fundamental current sharing and ensuring accuracy, that architecture is agnostic to the chemistry.”